1. Field of the Invention
This invention relates to a new proposal for the production of builder systems for use in surfactant-containing detergent and/or cleaning mixtures which may be made up as preferably phosphate-free mixtures of the type in question. More particularly, the invention seeks to achieve a further improvement in the so-called co-builder components in builder systems which contain fine-particle components insoluble under in-use conditions, more particularly corresponding mineral components, as their main builder in conjunction with at least one partly soluble co-builder, the co-builder normally being present in comparatively small quantities.
Fine-particle zeolite, more particularly zeolite NaA, is used as a phosphate substitute in modern detergents and cleaning preparations, being capable of binding the salts responsible for water hardness, above all calcium and/or magnesium ions, in the washing water and soil. However, so-called co-builders or co-builder systems also have to be used to a considerable extent, particularly in laundry detergents, above all to counter-act unwanted incrustation. Polymeric polycarboxylates, more particularly copolymers based on acrylic acid and maleic acid, in conjunction with soda are widely used for this purpose together with zeolite NaA. Complexing agents, such as salts of nitrilotriacetic acid (NTA) and phosphonic acid derivatives (HEDP), are additionally used. Co-builder combinations such as these in detergents and cleaning preparations of the type in question counter-act the precipitation of poorly soluble calcium salts and the resulting incrustation and discoloration of fabrics. Another desirable result is inter alia the greater whiteness of fabrics which can be achieved with builder combinations such as these.
2. Discussion of Related Art
In recent years, numerous proposals have been put forward with a view to at least partly replacing builder systems of the type described above by other components. These proposals have been prompted inter alia by the possibility of unwanted secondary effects after the used washing and cleaning solutions have been drained off into the wastewater system.
For example, crystalline layer-form sodium silicates have been described as substitutes or rather as partial substitutes for phosphates and zeolites. Thus, European patent application EP 164 514 describes a phosphate-free builder combination which mainly contains crystalline layer silicates with the selected structural formula NaMSi.sub.x O.sub.2+1.yH.sub.2 O, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, x preferably having a value of 2, 3 or 4. These layer silicates may be used as water softeners both separately and in detergents and cleaning preparations together with other builders or co-builders, such as phosphates, zeolite, other silicates, phosphonates and polycarboxylates. Reference is also made in this regard to the articles by F. J. Dany et al. "Kristallines Schichtsilikat--ein neuer Builder (Crystalline Layer Silicate-A New Builder)", Seifen-o/ le-Fette-Wachse 20/1990, 805 to 808 and by K.-H. Bergk et al. "Herstellung und Verwendung von Magadiit als Phosphatsubstitut in Waschmitteln (Production and Use of Magadiite as a Phosphate Substitute in Detergents)", Seifen-o/ le-Fette-Wachse 15/1987, 555 to 561 and the literature cited therein.
DE-OS 25 56 009 describes laundry detergents containing 12 to 25% by weight of zeolite, more particularly zeolite 4A, 5 to 20% by weight of a sodium silicate and a peroxy bleaching agent. According to this literature reference, unwanted deposits of the water-insoluble zeolite particles on the washing are said to be prevented by the use of 0.3 to 3% by weight of a polymer from the group consisting of carboxymethyl cellulose, lower alkyl cellulose, hydroxy lower alkyl cellulose, polyvinyl alcohol, polyvinyl acetate and/or polyvinyl pyrrolidone.
European patent application EP 010 247 describes laundry detergents containing surfactants in typical quantities, zeolite, alkali metal silicate and optionally a peroxy bleaching agent. The addition of water-soluble organic complexing agents from the group of substituted alkane diphosphonic acids and alkane triphosphonic acids, which are present in the form of their alkali metal and/or alkaline earth metal salts, is said to give a detergent which not only has a good primary washing effect, it also reduces fiber incrustation. Increased bleaching stability is achieved at the same time. The detergent contains 20 to 65% by weight of the fine-particle zeolite described in DE-PS 24 12 837 and 1 to 7% by weight of solid, powder-form sodium silicate with the molar composition Na.sub.2 O:SiO.sub.2 =1:2 to 1:2.2. Water-soluble organic complexing builders and other detergents may also be used.
In addition, corresponding combinations of mineral fine-particle main builder components insoluble under in-use conditions in combination with soluble co-builders, more particularly on the basis of polycarboxylates and derivatives thereof, are described, for example, in European patent applications EP 240 356, EP 337 217, EP 337 219 and EP 405 122.
Applicants' earlier German patent application P 41 06 880 relates to detergents, more particularly laundry detergents, containing surfactants, zeolite and alkali metal silicate and optionally a peroxy bleaching agent. By selecting a certain fine-particle hydrated zeolite with an average particle size of 1 to 5 .mu.m in combination with limited quantities of a solid selected alkali metal silicate, it is said to be possible to keep the detergent free from water-soluble organic complexing agents from the group of substituted phosphonates, free from polymeric polycarboxylates and free from alkali metal carbonates. Despite this, satisfactory washing results are obtained, even in regard to secondary effects, i.e. in regard to the particular percentage ash and incrustation contents.
The problem addressed by the teaching of the present invention was to resort to detergent and cleaning formulations of the type mentioned at the beginning in which combinations of fine-particle, insoluble, mineral main builder components with incrustation-preventing co-builders are used to replace the previously typical phosphate-based builder system. More particularly, the invention sought to provide co-builders which, on the one hand, would be highly effective in use, but which on the other hand could be regarded as comparatively unproblematical mixture components in the wastewater on completion of the washing and cleaning process. The invention sought to solve this problem above all with co-builder components based on derivatized natural substances which would be accessible to natural degradation processes and which would not initiate any unwanted secondary effects, for example the remobilization of heavy metals.